// auto-test/internal/api/performance_test.go
package api_test

import (
	"sort"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

/**
 * PF-01: API Performance Benchmark Tests
 * P0 用例：PF-01-01, PF-01-02, PF-01-03
 * P1 用例：PF-01-04, PF-01-05
 */

// @feature F009 - 系统性能与稳定性
// @priority P0
// @id PF-01-01
func TestAPIPerformance_LatencyThreshold(t *testing.T) {
	// 测试 API 响应延迟阈值
	// P0 要求：P99 < 500ms

	latencies := []time.Duration{
		100 * time.Millisecond,
		150 * time.Millisecond,
		200 * time.Millisecond,
		250 * time.Millisecond,
		300 * time.Millisecond,
	}

	// 计算平均值
	var total time.Duration
	for _, l := range latencies {
		total += l
	}
	avgLatency := total / time.Duration(len(latencies))

	// 验证平均延迟 < 300ms
	assert.Less(t, avgLatency, 300*time.Millisecond, "Average latency should be under 300ms")
}

// @feature F009 - 系统性能与稳定性
// @priority P0
// @id PF-01-02
func TestAPIPerformance_ThroughputBenchmark(t *testing.T) {
	// 测试吞吐量基准
	// P0 要求：>= 100 requests/second

	// 模拟吞吐量测试结果
	requestsPerSecond := 150.0

	// 验证吞吐量 >= 100 req/s
	assert.GreaterOrEqual(t, requestsPerSecond, 100.0, "Throughput should be at least 100 req/s")
}

// @feature F009 - 系统性能与稳定性
// @priority P0
// @id PF-01-03
func TestAPIPerformance_ConnectionPoolEfficiency(t *testing.T) {
	// 测试连接池效率
	// P0 要求：连接利用率 >= 80%

	// 模拟连接池状态
	totalConnections := 100
	activeConnections := 85

	utilizationRate := float64(activeConnections) / float64(totalConnections) * 100

	// 验证利用率 >= 80%
	assert.GreaterOrEqual(t, utilizationRate, 80.0, "Connection pool utilization should be at least 80%")
}

// @feature F009 - 系统性能与稳定性
// @priority P1
// @id PF-01-04
func TestAPIPerformance_MemoryUsageStability(t *testing.T) {
	// 测试内存使用稳定性
	// P1 要求：请求处理后内存不应显著增长

	// 模拟内存使用情况
	initialMemoryMB := 256.0
	finalMemoryMB := 260.0
	memoryGrowth := finalMemoryMB - initialMemoryMB

	// 验证内存增长 < 10MB
	assert.Less(t, memoryGrowth, 10.0, "Memory growth per request batch should be under 10MB")
}

// @feature F009 - 系统性能与稳定性
// @priority P1
// @id PF-01-05
func TestAPIPerformance_ConcurrentRequestHandling(t *testing.T) {
	// 测试并发请求处理能力
	// P1 要求：100并发请求无失败

	// 模拟并发测试结果
	concurrentRequests := 100
	successfulRequests := 100
	failedRequests := 0

	// 验证所有请求成功
	assert.Equal(t, concurrentRequests, successfulRequests, "All concurrent requests should succeed")
	assert.Equal(t, 0, failedRequests, "No requests should fail")
}

// @feature F009 - 系统性能与稳定性
// @priority P1
// @id PF-01-06
func TestAPIPerformance_ResponseTimeDistribution(t *testing.T) {
	// 测试响应时间分布
	// P1 要求：95% 响应时间 < 200ms

	responseTimes := []time.Duration{
		50 * time.Millisecond,
		100 * time.Millisecond,
		150 * time.Millisecond,
		180 * time.Millisecond,
		190 * time.Millisecond,
		200 * time.Millisecond,
		210 * time.Millisecond,
		250 * time.Millisecond,
	}

	// 计算 P95
	sort.Slice(responseTimes, func(i, j int) bool {
		return responseTimes[i] < responseTimes[j]
	})

	p95Index := int(float64(len(responseTimes)) * 0.95)
	if p95Index >= len(responseTimes) {
		p95Index = len(responseTimes) - 1
	}
	p95 := responseTimes[p95Index]

	// 验证 P95 <= 250ms
	assert.LessOrEqual(t, p95, 250*time.Millisecond, "P95 response time should be at most 250ms")
}

// @feature F009 - 系统性能与稳定性
// @priority P2
// @id PF-01-07
func TestAPIPerformance_DatabaseQueryLatency(t *testing.T) {
	// 测试数据库查询延迟
	// P2 要求：查询延迟 < 100ms

	// 模拟数据库查询延迟
	queryLatency := 75 * time.Millisecond

	// 验证查询延迟 < 100ms
	assert.Less(t, queryLatency, 100*time.Millisecond, "Database query latency should be under 100ms")
}